Panels from settled particles liquid binder and absorbent layer

ABSTRACT

The invention is concerned with wall panels and other construction units comprising a mixture of solid particles and liquid resinous bonding agent, said mixture being distributed on a base in such a manner that the volume of bonding agent exceeds the volume of the spaces between said solid particles. The solid particles are now allowed to settle and the excess bonding agent is allowed to rise to the top of said solid particles so as to form an outer layer, into which one side of an absorbent layer is applied to absorb the bonding agent, which finally is cured. In this manner there will be obtained a strong composite construction unit having a smooth surface.

United States Patent [72] Inventors lliarlhhulohenssong Karl OsltarWilrholm, both of l lluslrvarna,

Sweden [21] Appl. No. 788,806

[22] Filed Jan. 3, 1969 [45] Patented Oct. 26, 1971 [73] Assignee CebernAlrtiebolag .llonkoping, Sweden [32] Priority Jan. 119, 1968 [33] Sweden[54] PANELS FROM SETTLlEI) PARTICLES LIQUID BINDER AND ABSORBIENT LAYER[56] References Cited UNITED STATES PATENTS 3,440,189 4/1969 Sharp156/622 3,490,969 1/1970 Schiff 156/622 FOREIGN PATENTS 898,317 6/1962Great Britain 156/622 Primary Examiner-Leland A. SebastianAttorney-Albert M. Parker ABSTRACT: The invention is concerned with wallpanels and other construction units comprising a mixture of solidparticles and liquid resinous bonding agent, said mixture beingdistributed on a base in such a manner that the volume of bonding agentexceeds the volume of the spaces between said solid particles. The solidparticles are now allowed to settle and the excess bonding agent isallowed to rise to the top of said solid particles so as to form anouter layer, into which one side of an absorbent layer is applied toabsorb the bonding agent, which finally is cured. In this manner therewill be obtained a strong composite construction unit having a smoothsurface.

PANELS FROM SETTLED PARTICLES LlIQUID BKNDER AND ABSORBIENT LAYER Thepresent invention relates to the manufacture of flat or curved units,wall panels or the like for containers, silos, pipes, walls, roofs,floors or other building units, for example. A particular object of theinvention is to manufacture units which are durable, tight, strong andrelatively cheap to manufacture. According to the invention this isachieved by a combination of manufacturing steps including spreading outa mixture of solid particles and liquid resinous binder on a base, thequantity of said binder exceeding the volume of the spaces between thesolid particles, subsequently allowing the solid particles to settle,forming from the excess binder an outer layer, inserting into said layerone side of an absorbent layer to at least partially absorb this excessand finally curing said binder in a suitable known manner.

According to one embodiment described, by way of example, with referenceto the accompanying drawings in which H6. 1 shows a section of a layerof the panel during manufacture,

MG. 2 shows this layer ready made and FIG. 3 illustrates a later stagein the manufacture.

The manufacture may be carried out in the following manner:

A preferably uniform layer 3 of a mixture of liquid resinous binder andsolid particles is spread by means of a scraper or doctor knife 2, or insome other way, onto a preferably fiat, nonabsorbent base l (for examplea sheet of stainless steel) treated with release agent. The quantity ofbinder should exceed the volume of the spaces between the solidparticles. When the mixture has been spread out the solid particles 4settle on the base (FIG. 2) and at the same time air bubbles rise to thesurface.

The time taken before sedimentation has taken place and the air bubbleshave ceased to rise to the surface is, inter alia, de endent on thedensity and size of the solid particles and the viscosity and surfacetension of the liquid binder. The excess binder rises to the surface andforms an outer layer 5. The outer layer 5 is now combined with anabsorbent layer 6 (for example corrugated board placed transversely,FIG. 3) which is pressed down into the outer layer so that the excessliquid binder will be absorbed into the absorbent layer 6. On top of theabsorbent layer 6 is now possibly applied a layer 8 with release agentapplied on a reversed sheet 7, similar to the layer 3, 5, with theexcess resinous binder 5 facing the absorbent layer 6 so as to cause thelatter to absorb the resinous binder 5. When the resinous binder hascured a rigid hart product is obtained.

As is clear from FIG. 3, there are provided spacing runners 9 betweenthe sheets 1 and 7 which, with sufficient accuracy, give the finishedproduct the correct thickness and ensure that it will be parallel andflat.

in order to produce curved constructions, for example segments forcylinders, the layer 3 is spread as now described onto mouldable sheetson a flat base. When the layer 3 has settled, an intermediate layer orabsorbent layer of sand mixed with a deficiency of polyester and curingagent is spread to the desired thickness on one of the sheets. The sheetis then shaped to the desired radius. When this has been clone, theouter layer applied on the second sheet is placed on the top side ofsaid absorbent layer. The absorption capacity of the absorbent layermust be such that it absorbs a suitable quanti' ty of the excess liquidbinder. if the absorbent layer has too great an absorption capacity, thesettled part 4 is leached, which causes unsatisfactory adhesion betweenthe layers. If the absorption capacity is insufficient, a layer willremain between the absorbent layer 6 and the settled layer 4. When theliquid binder has solidified, the intermediate layer obtained in thisway will have greater shrinkage than the two other layers whereshrinkage is practicallly eliminated. Shrinkage tensions thus arisingmay cause cracking and/or deformation.

The liquid resinous binder may consist, for example, of an iso hthalic,phthalic, bisphenolic or other polyester to ether wit a suitable curingagent, for example in the form 0 hexamethylenetetramine. Thesesubstances are only mentioned as examples which are suitable, and which,as is well known in the art, will harden or cure" without theapplication of extra heat or pressure.

The solid particles may consist, for example of sand having, for examplean average particle size of 0.15 mm., of the type Baskarp-sand No. 7,"cement, granular slag, metal powder or iron powder, etc. The absorbentlayer may consist, for example of a mixture of sand with a deficiency ofpolyester or concrete or corrugated pasteboard (so-called "Tvarwell).

What we claim:

ll. Method ofmanufacturing flat or curved units, wall panels or thelike, comprising the steps of spreading out a mixture of solid particlesand liquid resinous binder on a base, the quantity of said binderexceeding the volume of spaces between the solid particles, subsequentlyallowing the solid particles to settle and to form a settled layer ofparticles with binder therebetween, forming from the excess binder anouter layer, inserting into said outer layer one side of an absorbentlayer to absorb at least partially said excess binder, and finallyallowing said binder to harden.

2. Method according to claim 1, wherein a similar unit consisting of asettled layer of solid particles with binder therebetween and an outerlayer of excess binder is applied on an other opposite side of saidabsorbent layer with the excess binder facing said opposite side, afterwhich the binder is allowed to harden on both sides of the absorbentlayer simultaneously.

t l t a l

2. Method according to claim 1, wherein a similar unit consisting of asettled layer of solid particles with binder therebetween and an outerlayer of excess binder is applied on an other opposite side of saidabsorbent layer with the excess binder facing said opposite side, afterwhich the binder is allowed to harden on both sides of the absorbentlayer simultaneously.